Noise-induced hearing loss continues to be one of the most common occupational disorders, even in OSHA compliant workplaces. Prevention of occupational hearing loss is a priority of the National Occupational Research Agenda (NORA). The Daily Exposure Monitoring of Noise (DEMON) study is a worksite intervention trial of new technology to reduce occupational noise-induced hearing loss through daily noise exposure monitoring. Noise-exposed workers will be recruited to wear an "Exposure Smart Protector" (ESP) device in place of their customary hearing protection. The ESP device functions as a combined hearing protector and noise dosimeter, measuring a worker's daily noise "dose" as well as peak noise exposures inside of the hearing protectors. Workers receive daily feedback about noise exposures in order to optimize hearing protection usage. Rates of hearing loss occurring in the 200 intervention subjects will be compared to rates in 400 controls who will receive enhanced education and hearing protector fit testing using the FitCheck system. This revised grant submission includes important new preliminary data indicating that the Exposure Smart Protector device is both tolerated by workers for long term use as a form of hearing protection, and also demonstrates potential to reduce occupational noise-induced hearing loss. Relevance: Effective use of hearing protection is a critical aspect of hearing loss prevention, yet in real world settings, hearing protection effectiveness varies widely. Analysis of hearing loss rates for a large industrial employer (Alcoa) indicates differential usage of hearing protection may account for the majority of occupational hearing loss cases. There are currently no national guidelines for ensuring correct fit and function of hearing protection, and there is an urgent need to find ways to promote the correct use of hearing protective devices. The results of this study could have major implications for hearing conservation practice, creating important new opportunities for the prevention of noise-induced hearing loss.